The present invention relates to a water-soluble color-stabilized food containing ascorbic acid or its salt and at least one water-soluble color selected from the group consisting of coal-tar color, anthocyanin color and carthamus yellow, and particularly concerns with said food further containing sorbic acid and/or its salt or a salt of sulfurous acid so that the water-soluble color can be stably retained.
The present invention also relates to a water-soluble color-stabilized food containing ascorbic acid or its salt and at least one water-soluble color selected from the group consisting of coal-tar color, anthocyanin color and carthamus yellow, and particularly concerns with said food further containing sorbic acid and/or its salt and a salt of sulfurous acid so that the water-soluble color can be stably retained.
Color additives have been widely used for various products such as foods, pharmaceutical compositions, quasi-drugs, cosmetics, livestock feeds and so on. Colors widely used include synthetic colors with assured safety such as coal-tar color; and naturally occurring colors (hereinafter referred to as xe2x80x9cnatural colorsxe2x80x9d) such as anthocyanin color, flavonoid color, quinone color, betacyanine color and azaphyllone color.
However, these colors are known to discolor or fade due to photolysis by light irradiation, oxidation, heat or the like. In recent years, there is a tendency to pale the color of a food using a reduced amount of a color for representation of naturalness. As a food color becomes paler, the food discolors or fades more markedly by exposure to light, air oxidation, heat or the like. Therefore, the prevention of color fading is now more important than before.
Various measures have been considered to prevent the discoloration and fading due to colors with poor stability (an effect of preventing the discloration and fading will be hereinafter referred to as xe2x80x9cstabilizing effectxe2x80x9d). For example, the addition of specific materials has been proposed for stabilization of colors. Typical examples of such materials are synthetic compounds such as dibutylhydroxytoluene (BHT); ascorbic acid/erythorbic acid, and their derivatives; naturally occurring flavonoids such as catechin and chlorogenic acid; sulfurous acid (Adams, J. B., and Ongley, M. H., Campden Food Pres. Res. Assoc., Tech. Bull., p.23 (1972)) and the like.
The use of synthetic compounds, e.g. dibutylhydroxytoluene (BHT), tends to abate with the increase of nature-oriented tendency.
Ascorbic acid/erythorbic acid and their derivatives stabilize only a limited colors such as carotenoid colors. Moreover, when used for other colors, these compounds promote the fading of other colors, far from stabilizing other colors. This problem may arise in foods originally containing ascorbic acid or the like. Recently ascorbic acid or like vitamin C components are profusely incorporated into foods to improve the nutrition level, posing a serious problem of color fading (Comparative Examples 1-3).
Naturally occurring flavonoids such as tea extracts containing catechin, chlorogenic acid contained in coffee or sunflower seeds and caffeic acid derivatives produce a low stabilizing effect, especially a low thermally stabilizing effect.
Sulfurous acid reportedly effectively inhibits the fading of anthocyanin colors (Z Lebensm Unters Forsch (1992) 194,524-526). When used singly, sulfurous acid gives only a low stabilizing effect. When used in a large amount to increase the stabilizing effect, sulfurous acid significantly impairs the flavor of the food and may accelerate the fading of anthocyanin colors in the food (Ditto, FIG. 2).
A salt of sorbic acid is generally used as a preservative and scarcely stabilizes water-soluble colors when used singly. In other words, a salt of sorbic acid is not known as a color stabilizer.
Currently there is a demand for a method of coloring a food with a color so stabilized as to avoid discoloring or fading, especially a demand for means for stably coloring a food with a color without a likelifood of discoloring or fading, when ascorbic acid is originally contained in the food or added in a large amount.
Therefore, it is desired to develop a method of stabilizing a color in a food to effectively prevent the discoloration and fading and to give the color a high resistance to light and heat.
The present inventors conducted extensive research to overcome the foregoing problems and found the following. When a food is colored with at least one water-soluble color selected from the group consisting of coal-tar color, anthocyanin color and carthamus yellow, the food is stably colored with said color(s) by incorporating sorbic acid and/or its salt or a salt of sulfurous acid into the food, especially into the food containing ascorbic acid or its salt.
The following was also discovered. When a food is colored with at least one water-soluble color selected from the group consisting of coal-tar color, anthocyanin color and carthamus yellow, a higher stabilizing effect is exhibited and high light and heat resistances not heretofore attained are shown by the water-soluble color when sorbic acid and/or its salt and a salt of sulfurous acid are incorporated into the food, especially into the food containing ascorbic acid or its salt. Based on these novel findings, the present invention was completed.
The foods of the invention contain ascorbic acid or its salt, and are colored with at least one water-soluble color selected from the group consisting of coal-tar color, anthocyanin color and carthamus yellow.
Specific examples of such foods are non-alcoholic drinks such as lactic acid beverages, lactic fermenting beverages, concentrated dairy beverages, fruit juice drinks, non-fruit juice drinks, fruit flesh drinks, functional drinks, clear carbonated drinks, fruit juice-containing carbonated drinks, fruit-colored carbonated drinks and like soft drinks; alcoholic drinks such as wine, wine soda, liqueur and cocktail; ices such as ice cream, popsicle-style ice candies and sherbets; Japanese-style confections such as rice crackers, those seasoned with soy sauce, millet-and-rice cakes, steamed buns and candies; Western-style cakes such as cookies, biscuits, crackers, pies, sponge cakes, Castella, doughnuts, waffles, custard puddings, caramels, candies, chewing gums, jellies, hot cakes and bread; snack foods such as potato chips; dairy products such as fruit yogurt and cheese; soybean processed foods such as bean milk; marmalade, jam, conserves and fruit syrup; pickles; meat-processed products such as hams, sausages, bacons, dry sausages and beef jerkies; fishery products such as fish-hams, fish-sausages, boiled fish paste, tubular rolls of fish paste, light puffy cakes made of ground fish and deep-fried fish; dried fishery products; sea foods such as seasoned sea-urchin eggs, squid guts pickled in salt and dried shellfish; products boiled in sweetened soy sauce, the products being inclusive of seasoned seaweeds, small fish, shellfish, dried cuttlefish, vegetables, edible wild plants, mushrooms and sea tangles; curried foods such as instant curry and retort curry (retort pouch foods); seasonings such as ketchup and mayonnaise; foods for electronic oven and frozen foods.
The foods for use in the present invention include foods containing ascorbic acid or its salt as the component of raw materials for foods and foods with ascorbic acid or its salts incorporated therein to improve the nutritive condition. These foods are found to contain ascorbic acid or its salt when analyzed to determine food components by a method (such as disclosed in xe2x80x9cMethod of Analyzing Food Additives in Foodsxe2x80x9d, edited by the Ministry of Health and Welfare, Environmental Health Bureau, food chemistry section, issued by Kodansha Co., Ltd., 4th edition, pp. 283-302).
The term xe2x80x9cascorbic acidxe2x80x9d used herein refers to ascorbic acid or erythorbic acid. The term xe2x80x9csalt of ascorbic acidxe2x80x9d is used herein to mean at least one member selected from the group consisting of sodium salt, potassium salt and calcium salt of ascorbic acid or erythorbic acid.
The result as contemplated by the invention can be achieved when ascorbic acid or its salt is contained in the food in an amount of preferably at least 0.001% by weight, more preferably 0.001 to 0.1% by weight, based on the total amount of the food. The use in excess of 0.1% by weight tends to promote the color fading.
The water-soluble color for coloring the foods of the invention is at least one water-soluble color selected from the group consisting of coal-tar color, anthocyanin color and carthamus yellow. Among said species, coal-tar color shows a marked stability to light. These colors may be used in the food either alone or in combination. The foregoing colors may be used in mixture with other natural colors or with plants, animal bodies, microorganisms, their processed products, their pressed juice, refined products of their extracts, etc. all of which contain natural colors. Examples of the other natural colors are cochineal extract, shikon color, madder color, lac color and like quinone colors; Japanese persimmon color, carob germ color, licorice oil extract, sandal wood red, sappan color and like flavonoid colors; beet red and like betacyanine colors; monascus yellow, monascus red and like azaphyllone colors; turmeric oleoresin, kusagi color, gardenia blue, gardenia yellow, gardenia red, spirulina color, etc.
Examples of the coal-tar color to be used in the present invention are Acid Red 27, Acid Red 51, Food Red 17, Acid Red 18, Acid Red 92, Acid Red 94, Acid Red 52, Acid Yellow 23, Food Yellow 3, Food Blue 2, Acid Blue 74, Food Green 3, etc. all of which are food colors.
Examples of the anthocyanin color useful in the present invention are red cabbage color, red rice color, elderberry color, cowberry color, gooseberry color, cranberry color, salmonberry color, perilla color, thimbleberry color, strawberry color, dark sweet cherry color, cherry color, hibiscus color, black huckleberry color, grape juice color, grape skin color, black currant color, black berry color, blueberry color, plum color, whortleberry color, boysenberry color, mulberry color, purple sweet potato color, purple corn color, purple yam color, raspberry color, red currant color, loganberry color, red radish color and so on.
A salt of sorbic acid to be used in the present invention is any one wherein a salt is combined with sorbic acid by ionic bond. Examples of the salt are sodium salt, potassium salt, calcium salt, etc. The sorbic acid or its salts may be used either alone or in combination. A preferred amount of sorbic acid or its salt to be used is 0.1 to 300 ppm. More than 300 ppm would not increase the effect of preventing the color fading, whereas less than 0.1 ppm would fail to produce the effect contemplated by the invention. A more preferred amount is 25-300 ppm which gives the result of the invention in a remarkable degree.
The salt of sulfurous acid to be used herein is at least one member selected from the group consisting of sodium sulfite, sodium hyposulfite, sulfur dioxide, potassium pyrosulfite, sodium pyrosulfite, potassium hydrogensulfite and sodium hydrogensulfite. The amount of a salt of sulfurous acid to be used is preferably 0.1 to 200 ppm, more preferably 1 to 200 ppm. Less than 0.1 ppm would fail to fully produce the contemplated effect of the invention, and more than 200 ppm would be likely to pronouncedly impair the flavor of the food because the flavor peculiar to sulfurous acid salt prevails.
When sorbic acid and/or its salt is used in combination with a sulfurous acid salt, the ratio (weight ratio) of sorbic acid and/or its salt:sulfurous acid salt is in the range of preferably from 1:10 to 100:1, more preferably from 1:1 to 10:1.
According to the present invention, the color of a food is stabilized by incorporating sorbic acid and/or its salt or a salt of sulfurous acid into the food, the food containing ascorbic acid or its salt and being colored with at least one water-soluble color selected from the group consisting of coal-tar color, anthocyanin color and carthamus yellow.
According to the present invention, the color of a food is stabilized by incorporating sorbic acid and/or its salt and a salt of sulfurous acid into the food, the food containing ascorbic acid or its salt and being colored with at least one water-soluble color selected from the group consisting of coal-tar color, anthocyanin color and carthamus yellow.
Optionally the sorbic acid and/or its salt and/or a salt of sulfurous acid may be incorporated into food materials in the course of manufacturing the food or may be incorporated into water-soluble colors in the course of production or into additives or the like.
The present invention is practiced not only for foods but for other products containing ascorbic acid or its salt and a water-soluble color. Examples of such products include pharmaceutical compositions, quasi-drugs, cosmetics and livestock feeds. The water-soluble color in these products can be stabilized according to the present invention.
Specific examples of said products are tablets, capsules, health drinks, lozenges, gargles, tooth paste, stomatic soft drinks, halitosis preventives, skin lotion, etc. The colors derived from components of such products as well as the water-soluble colors added can be stabilized according to the invention. In the case of livestock feeds, it is possible according to the invention to stabilize not only the water-soluble colors added but colors originated in components of cat foods, dog foods, feeds for ornamental fish, feeds for cultured fish and the like.
The present invention will be described below in more detail with reference to the following Experiment Examples, Examples and Comparative Examples. However, the invention is not limited to the Examples at all.